Though I am a programmer, I have never written for any Apple device. As such, my iOS-specific knowledge and familiarity with their API is nearly non-existent so please bear with me.
I would like to create an action from the lock screen (swipe, double tap clock, whatever) that would unlock and immediately open the App Switcher (I am not interested in extensions ala SwitcherPlus or the like). I guess this means writing a small script, and I could use some help concerning the API and other basics (the core features, shouldn't need any fringe stuff). While I am willing to get into the nitty gritty if need be, I am open to other solutions. Even something as high-level as chaining several Activator responses together would be fine.
I see Ruby under Cydia/Scripting (Telesphoreo). Though I'd slightly prefer Python or even Bash, being that my purposes are fairly minor Ruby would be just fine. I would rather not use Objective-C. While my original goal is the behavior described above, I can see myself wanting to do similar things in the future so some tips towards general know-how would be much appreciated.
If it is not clear, this a purely personal project. I am not at all concerned with packaging, sharing, backwards compatibility, commercial appeal, etc
PS - I have, until this point, set my Cydia viewing to "hacker" but not "dev". Does this endeavor indicate that I should up it to dev? The term seems a little generous, but if it opens up packages that I will need...
EDIT: I use an iPhone 4S, iOS 5.0.1
I don't think that this is possible in any scripting language. For one reason: You'll need to do code injection to achieve these goals (MobileSubstrate).
1) If you want to detect user interaction, you'll have to add ways to detect it or hook implementations which are already there. Even if you just wanna use Activator, you'll still have to develop a binary to register itself with Activator -> objC
2) There is no known way (at least to me) to interact with SpringBoard via scripts the way you want. So you'll have to make a binary which would execute the opening of the switcher.
I hope someone will have a better answer for you, but I'm very very sure that you won't get around using C/objC
There is a tool called http://www.cycript.org/ which is a bridge between JavaScript and objC, but I have never seen it being used for more than investigating.
Related
I just saw this 2012 video from LinuxConf.au about Erlang in production.
There's a part on the video where Bernard says no big Erlang projects use Hot Code Loading apart from Ericsson, because it's really hard to guarantee things will work. It's around minute 29.
Is that still true? Are there tools to help test a hot code load or or make it easier nowadays?
This is not true. Every Erlang user uses hot code loading to his advantage in one way or another -- whether it is for development, testing, troubleshooting, one-off fixes, or full scale deployments. This is one of the major Erlang advantages. Rather unique too.
For example, WhatsApp, one of the biggest Erlang users, relies on hot code loading for almost all code pushes.
I have personally worked with hot code loading in scenarios where each change was well understood and often performed by the same person who made the change. It works extremely well and good engineers don't have any problems doing this. Speaking of tools, loading modules one by one from Erlang shell using l(...). or all at once using l(). (see here) works just fine. Some prefer release-based tools like relx.
Others, like Ericsson, use enterprise-style deployments with hot code loading after rigorous testing of clear-cut releases and patches. The goal here is to upgrade without using spare capacity and special procedures for draining and shifting load. Operationally this may be simpler and more efficient than restarts, but testing can be more expensive.
It is difficult to know whether it is a feature widely or scarcely used. Nowadays there are plenty of Erlang systems out there. I can however think of reasons why and why not to use it, since I have been working with bot options for quite some time.
In favour of using it:
It is obviously quite useful during development to ensure a fast feedback cycle. I always develop with an open shell, and with functions to load code automatically as son as compile.
In the rare case you need to implement a monolithic application with high availability requirements, it is basically the only option
The main reason not to use it, as the presentation states: it is hard. Even if you manage to understand exactly how it works (which is not the hardest part).
It is not, in my opinion just a problem of tooling, but rather that you are getting a lot of intrinsic complications just by the fact that now your code is part of the mutable running state of the system. You basically end up having a long running system that changes behaviour, so you add those to the problems you already had:
You are no longer sure that restarting the system will not change behaviour on any fundamental way. So you will probably need to put extra care on making sure that whatever code you load, it is also written to disk.
Changing the way your modules work (i.e. loading new code) is very tricky unless a) you never break compatibility, b) you somehow figure out the order in which the modules should change or c) you assume the worst that can happen is a few crashes due to undefined functions, function or case clauses, etc, and hope for the best (the actual worst is when the new and old modules interact in unexpected ways while you haven't finished loading all of the new ones and the actually run some impossible logic).
You will almost certainly will end up killing some process running old code when loading new code at some point. Maybe your supervisors will help you, maybe not. In any case that could be very confusing and difficult to debug.
As the presentation also states, is very hard to test (if not impossible).
Etc.
Adding to all those, you are running a long living server with long living state, which is far from ideal.
So my advise is always that, if you could get away with a distributed application and rolling upgrades, you should do it. That option is much easier to handle, and in my experience, performs better overall.
I want to do unit testing in iOS. By default test classes are created using XCTest framework classes in Xcode 5. I have used SenTestingKit in earlier versions of iOS. What are the differences between these two frameworks? What are the advantages of XCTest framework. I googled for related documentation but I did not find any. Only thing I found is the interface classes to use inside the kit. Can anyone point me to the related resources.
Apple's documentation is notably lacking with regards to testing. It's a shame, because spending five minutes with XCTest made me fall for it. So, here are some docs that you may find useful.
First, stop and watch the WWDC video about testing: https://developer.apple.com/wwdc/videos/?include=409#409 (must be a registered developer)
Then, read about Bots. They're the real magic in XCTest. I'm currently setting up an environment of a Mac Mini running Mavericks Server connected to a small array of iPod Touches, iPhones and iPads that will simultaneously run my unit tests and report back. It's damn near magic.
https://developer.apple.com/library/ios/documentation/IDEs/Conceptual/xcode_guide-continuous_integration/000-About_Continuous_Integration/about_continuous_integration.html#//apple_ref/doc/uid/TP40013292
All that said, I don't know SenTest well enough to compare the two. But I am learning XCTest, so here are a few thoughts on what I'm really digging about it so far.
It's already there. There's nothing to download, and you can make your test class objects at the same time as you make that which you wish to test. Rad.
Because it's integrated so deeply with Xcode, you can see test coverage in the gutter. You can also use Companion View to see the testers from source, or the source from tester methods. Also, it will always be up to date - no waiting to fix integration with Xcode because Apple "broke" something.
Continuous Integration. The bots are just magical, and they're so easy. You also get Git hosting, which is a small fringe perk, but more so if you prefer your Git internally hosted but don't want to pay for GitHub Enterprise.
And, a few cons for measure:
Lack of Documentation. Asking me to read the headers for a list of assertions is a ballsy move. I have no doubt Apple will fix this soon, but not soon enough.
You are tied to Xcode a little more deeply. Not really a con for development, but scripting XCTest isn't as elegant as other options may be.
Continuous Integration requires OS X Server. It can be on the same machine if you really want, but it's $20 to buy, even if you owned Mountain Lion Server. I am not at all bitter about this one (ha).
My two cents. Hope it helps. I'd really recommend watching that video I linked to - they do live test creation and make a really compelling case for unit testing in general, regardless of if you use XCTest.
XCTest are included by default with ios7 and integrate better with the new continuous integration functionality.
https://developer.apple.com/technologies/tools/
It seems the advantages are presently few, but that will hopefully change over time, so starting a community wiki to document some:
The XCTAssert… family of macros can handle you leaving out the format parameter (used for commenting why a test should pass) entirely. This is handy for keeping simple tests (where it's obvious from the test itself what it's doing) clean in the editor. STAssert… required us to make the format parameter nil or some such instead.
There's a generic XCTAssert() macro, which feels neater than bodging some types of check into STAssertTrue.
I know a lot of questions have been asked about VB6 migration (and I've read most of them), but I'm still not entirely certain on what the best way to go about this is.
We have a client that we built an order tracking application for about a decade back and they came to us this week saying they were having some issues with it. The app was written entirely in VB6, which has been something of a hassle as tracking down the necessary tools to work with a project so old took some considerable effort. In an effort to make any future maintenance less of a headache, my boss wants to pitch the idea to them of updating the app to .net and wants to know what exactly that would entail. I've never done anything like this before, but what I've read (both here and elsewhere) suggests that Microsoft's "auto-update" from VB6 to .net simply doesn't work very well and I'd pretty much have to rebuild the app from the ground up.
To get to the crux of my question: is this the case? Would I pretty much just need to rewrite it, or is there another means of going about this that could/would save me a lot of time/effort?
Any insight would be greatly appreciated.
VB6 and VB.NET are radically different. The syntax has changed, and so has the underlying structures, forms, custom controls, and almost every single aspect you can possibly think about.
A complete redesign and reassessment of needs and functionality is imperative. With .NET the plethora of new libraries and features supersede the antiquated VB6 libraries, OCXs, etc. Also if you feel bold, you can migrate your code to C# and other CIL languages aside from VB.
Out of hand, the Microsoft migration tool will not do much. Moreover, it also depends on whether you have your business logic well separated from your GUI. Otherwise, it will make it even harder. Depending on the size of your application, it might make it quite expensive. Another possible solution you might consider is to run your app in a virtual environment or on a remote app http://technet.microsoft.com/en-us/library/cc730673(v=ws.10).aspx that will ease the deployment pain.
I have also researched this topic.
Try the smart rewrite solution that converts 95% of the code automatically.
first, run your app through the assessment wizard to determine estimated costs and resources needed.
http://visualwebgui.com/Gizmox/Solutions/InstantbCloudmoveb/tabid/744/Default.aspx
I'm going to develop a collaborative site, and one of the features will be collaborative editing with realtime changes. i.e. when two or more users are editing the same doc, they can see each other changes as soon as they happen.
I have some experience with Ruby on Rails, so I was thinking about using EventMachine, but with all this hype around Node.js, I am know considering using it instead. So, what would be the main benefits of using Node.js instead of EventMachine?
tl;dr
What are the main differences between EventMachine and Node.js (besides the language)?
EventMachine has nothing to do with Rails apart from them both being written in the same language. You can get EventMachine as bare as Node.js; all you have to do is not add libraries to your project. In my experience the EventMachine libraries (like em-http) are much nicer than anything for Node. And you can use fibers instead of callbacks to avoid callback hell. Complete exception handling is pretty much impossible in Node because of all the callbacks. Plus Ruby is a nicer, more complete language than Javascript.
I tend towards the "use what you know" (even if it's a heavier architecture). Because of that, I don't see it being quite as simple as "EventMachine vs NodeJS." Mainly, the difference can be summarized as this:
NodeJS is a framework/language that was written to handle event based programming in JavaScript. That is its driving force. It's not an after thought, or a third party mechanism. It's baked right in to the language. You create callbacks/events because that's how the language is built. It's not a third party plug in, and doesn't alter your workflow.
EventMachine is a gem in Ruby that gives developers access to some of the goodness of the event based programming model. It's heavily used and well tested, but not baked directly in to the language. Both are locked to one CPU, but with event programming at Nodes core, it still has a leg up. Ruby wasn't written with concurrency in mind.
That said, technical problems can be overcome. The more important questions (from my view) that should guide your decision are these:
What will your production environment look like? Do you have complete control over the server? Can you host it however you want? Or will it be on a shared system to start with, and then you have to expand on that?
Do all the developers on your team have the ability to learn a new language very fast? How fast will they be able to understand an event-based language like JavaScript for the middle tier?
Do you need all of the architecture that Rails gives you (full Testing framework, scaffolding, models, controllers, etc)? Or is that overkill?
There are quite a few technical differences between the two. One is a language, one is a framework. Really, how heavy of a stack you want to run? How much learning will your developers have to do? Do you want a full stack the gives you a lot of niceties, that you may not use, or do you want a bare bones set up that runs extremely fast and concurrent, even though you may have to write extra boiler plate code and learn a new lanugage?
While Rails is not as heavy as some web application architectures, you're still going to need more processor power than you would to handle a similar amount of throughput in NodeJS. Assuming quality code for both systems. Bad code written on either stack is going to prevent the stack from shining. It really comes down to- Do you really want to learn a whole new way of doing things, or utilize your current understanding of Ruby to get things off the ground fast?
I know it's not really a definitive answer, but I hope this helps guide you to a decision!
One thing worth mentioning is the production story. EM, like most Rack stuff, has plenty of testing and monitoring tools available that are well tested, whereas Node.js falls well short in this respect.
At the time of writing, it seems almost impossible to get clear metrics from Node to answer questions like 'Do I need to scale'. There are options starting to form out there from the likes of Joyent, and always the roll-your-own argument, but nothing anywhere near tools such as NewRelic.
Node.js is very good from a performance / configurability point of view, but personally I wouldn't host it in production just yet.
Node.js
You get far better control low level control over what's going in. You can include general libraries to build on top of node.js to tweak your level of abstraction to your own liking. For example you can use connect or express depending on whether you want a view engine written for you.
You can use socket.io or now depending on how much you want your client-server connection abstracted. You can opt to include any of numerous MVC libraries or write your own.
Event-Machine
An asynchronous IO library just like node.js
It comes down to a Ruby vs JavaScript preference, how much flexibility you want with abstractions or lack of abstractions and whether you want to use node as your actual web server.
a detailed view at confusion has already been proposed... just a personal view
[] node.js will be better, if you are ready to learn and experiment more than you think because:
it's thread mechanism is awesome (inspired from that of 'erlang')
you can build a purpose specific server (easily) which will be real productive
I'm working on Windows XP/Delphi 7. I need to add some procedures (or functions) inside a program that is running, and I do not want to re-compile it once again after I finished it.
I just have a host application with 5 functions to send different types of alarms, but there are other new alarm types, so I have to do new functions to send those alarms, but I should not re-build the host application. I have a class named TAlarmManager that it's invoked calling those functions.
Maybe a plugin?? OK, but how can I "insert" new functions??? Tutorial, manual, book, etc.. for learning about this, or any advice on how to do this???
I have studied plugins (I'm totally new on this theme), but no one "talks" about adding functions to a host application. It seems to me that plugins add functionality from itself, I mean, they have been developed with self code to do something, not to "add" code to the host application... How can I do this??
For the technical side: How does the Delphi IDE do it? That would be the first place for me to look.
To understand plugins, you must understand that you can't add new functions. You could but since the old code doesn't know how to call it, they wouldn't be called.
So what you do is you add a "register" or "start" function to your plugin. That start function gets a data structure as parameter which it can examine or extend. In your case, that would be the list of alarms. Alarms always work the same (my guess), so it can add additional alarms.
The main code will then, after registering all plugins, just walk over the list of alarms and invoke the standard alarm function on each of them. It no longer cares where each alarm comes from and what it really does.
The key here: You need to define an interface which both sides subscribe to. The main code calls the interface functions and your plugin code implements them.
Another option available is to use a scripting component to your project. One which works quite well is PascalScript. This would allow you to load external scripts after the fact and then run them as needed to interact with your application. As Aaron suggested you will also need to still provide an interface of some sort for your script to interact with your application.
See also Plugins system for Delphi application - bpl vs dll? here on Stackoverflow.
I'm not quite sure what you mean by "alarms", so I'm making a couple of assumptions.
1) If you don't need additional code for the alarms, I would try to make them data driven. Keep the different kinds of alarms in a database or configuration file, which makes it easy to update applications in the field without recompiling or reinstalling.
2) If you need special code for each alarm, you could use run time packages as plug-ins for your application. Search for Delphi runtime packages to get some ideas and tutorials. Here are a couple of links I found:
http://delphi.wikia.com/wiki/Creating_Packages
http://delphi.about.com/od/objectpascalide/a/bpl_vs_dll.htm
3) Scripting, as skamradt already mentioned. If it makes sense for your application, this could also let your customers write their own add-on functionality without requiring a recompile on your part.
You almost definitely want to use Pascalscript, as skamradt suggests. You should start here, and seriously consider this option. There are many possibilities that come out of being able to serialize live code as text. The only downside is possibly speed of execution, but that may not matter for your application domain. I would have upvoted skamradt, but I don't have enough reputation to upvote :)
Some time ago I was looking at a situation sort of like what you're describing.
My answer was .DLLs. I put the variable code in a .DLL that was dynamically loaded, the name specified in a configuration file. I passed in a record containing everything I knew about the situation.
In my case there was only a success/fail return and no screen output, this worked quite well. (It was commanding a piece of machinery.)
This sounds like a place where a scripting language or "Domain Specific Language" may make sense. There are several approaches to this:
Implement alarm functions in VBscript (.vbs files written in notepad) that accesses your Delphi code via COM API. Using the COM API gives you access to a large range of programming tools for writing functions, including Delphi. This is the most clumsy solution, but easiest to do. It may also be a benefit to your sales process, and it is always good to think about how to sell things.
Implement your own function language in Delphi. This way you can make it so easy, that your endusers can write their own alarm functions. If you do it as an expression evaluator, you can write an alarm as 2*T1>T2. There are several expression evaluators out there, and you can also write your own if they don't match your needs.
Use a predefined programming language inside your Delphi application, for instance, "Pascal Script", see http://www.remobjects.com/ps.aspx
You should take a look at PaxCompiler, like PascalScript it allows to load scripts, but you can even precompile them before for more performance. Look at the demos section for the solution of your problem.
As a side note, the web page really looks bad, but the package is really powerful and stable.
I think that the scripting solution it's good for this situation.
There are many scripting packages that you can evaluate:
Context Scripting Suite
Fast Script
RemObjects Pascal Script
TMS Scripter Studio
paxScript
Other packages that you can find on Torry, DSP, VClComponents,...
Regards.